Steps for conducting the experiment
General Instructions
Follow are the steps to be followed in general to perform the experiments in Advanced Network Technologies Virtual Lab.
- Read the theory about the experiment
- View the simulation provided for a chosen, related problem
- Take the self evaluation to judge your understanding (optional, but recommended)
- Go to the exercises section, choose a problem, and carefully read the problem description
- Write a script (or make necessary changes) to simulate the desired scenario in the code editor just below the problem statement
- Click on the 'Run' button to execute the simulation script
- Simulation with ns2: If the simulation was successful, and was instructed to create a trace file, contents of the trace file would be displayed in the area below the 'Run' button
- Simulation with ns3: If the simulation was successful, output of the program would be displayed in the area below the 'Run' button
- A trace file generated as a result of simulation with ns2 could be used for certain kind of analysis, which would be discussed in a later section
Experiment Specific Instructions
- Create the topology as shown in the exercises
- Set up the traffic flows
- Run the simulation
- Take measurements from by analyzing the trace file
- Alter the parameter(s) specified in the experiment, run the simulation and take the measurements again
- Repeat the above step until desired result is obtained
Trace File Analysis
A simple tool has been provided as part of this lab to analyze the trace files generated after simulation with ns2. A summary of the available options, and usage guide is given below.
Features List
Following is a list of functionalities provided by the Trace Analysis tool:
-
Trace file formats: Following trace file formats are
being supported:
- Wired
- Wireless (new format)
- Satellite -- currently redirects to wired mode
- Mixed -- when both wired and wireless connections are present in the simulation
-
General Statistics: To provide some common statistics
about the simulation being run. Currently displays only the simulation duration.
- Inputs: None
- Output: Text
-
Average Throughput: Computes total # of bytes received
by a node over the entire simulation duration
- Inputs: Node #
- Output: Number
-
Bytes Received: Plots cumulative count of bytes received by
a node over the entire simulation duration
- Inputs: Node #; for wireless scenario, trace levels (AGT, MAC, RTR)
- Output: Graph
-
End-to-end Delay: Plots the end-to-end delay delay encountered
by packets while moving from a source node to the destination node
- Inputs: Source node #, destination node #, scaling factor [optional] -- scaling factor helps to amplify the y-axis values
- Output: Graph
-
Packet Retransmissions: Plots # of retransmission(s) of
a given packet occurs between the source and destination nodes
- Inputs: Source node #, destination node #
- Output: Graph
-
Hop Count: Plots the # of hops traveled by a packet to reach
the destination node from the source node. It counts the destination node as well.
- Inputs: Source node #, source port #, destination node #, destination port #
- Output: Graph
Limitations
- For analyzing the problems in the "Satellite Networks" experiment, please use the Wired mode of analysis
- Analysis of trace files for mixed mode of simulations (wired & wireless) is not supported currently
- Outputs produced do not necessarily have accuracy for scientific publications. In particular, the plot of hop counts may vary a bit from the original count (in wireless mode) in cases when a packet has been forwarded to more than one node.
- The tool currently allows only a single instance of a given type of plot. For example, this doesn't let you plot end-to-end delays between multiple (source, destination) node pairs